Luminaire for residential roadway lighting

Abstract

A luminaire for roadway lighting using a one-piece reflector developing at least two collimated beams in each longitudinal direction. The collimated beams impinge on sloping faces of a refractor to diverge the beams into a regular pattern covering the street with a sharp cutoff at predetermined longitudinal distances from the luminaire. The refractor employs a compressed parabola comprised of radial sections of comparatively large focal length with steps and risers. The complex shape of the one-piece reflector may readily be produced by a reflector finish applied to a molded plastic matrix. In the luminaire, the prismatic surfaces of the inclined walls of the refractor diverge the formerly collimated beams in a carefully controlled manner to produce very uniform distribution of light.

We claim: 
     
       1. A one piece reflector for use in a luminaire, said reflector having a top wall with side walls essentially rectangularly oriented about a light source with said walls symmetrical about the centerline of the light source to form an open bottom reflector structure with rectangular corners, said walls comprising a stepped parabolic specular reflector producing at least two collimated beams on each side of said centerline, each side wall of the reflector including a plurality of internal steps adjacent the corners of the housing with an internally concave continuous midsection, each said step being generally perpendicular to the axis of the light source, the top wall having an outwardly domed arcuate midsection with essentially flat lateral sections outwardly of the domed section, said domed section including arcuate steps adjacent the axial ends of the centerline to combine with said sidewalls to produce said at least two collimated beams along each lateral side wall. 
     
     
       2. A reflector as claimed in claim 1, in which the side wall steps are arcuate relative to the axis of the light source. 
     
     
       3. A reflector as claimed in claim 1, in which each step has a shallow riser angled toward the center of the reflector. 
     
     
       4. A reflector as claimed in claim 1, in which successive steps toward the center of each wall are successively longer than the steps more adjacent the corners of the reflector. 
     
     
       5. A reflector as claimed in claim 1, in which said domed section includes arcuate steps about the centerline of the reflector adjacent the axial ends of the reflector.